Alcohol and Dementia: New Evidence Challenges Old Beliefs

Dr. JoAnn Manson, a professor at Harvard Medical School and Brigham and Women’s Hospital, addresses a recent study that reshapes our understanding of alcohol’s impact on dementia risk. 

For years, observational studies suggested alcohol could protect the heart, brain, and even extend lifespan. However, these findings were flawed, often comparing drinkers to nondrinkers who had quit due to health issues or medication conflicts, or to moderate drinkers with healthier lifestyles and higher socioeconomic status.Revised analyses and new research have since linked alcohol to increased risks of hypertension, heart disease, stroke, atrial fibrillation, heart failure, cirrhosis, various cancers (including gastrointestinal and breast), and reduced lifespan. 

A recent study published in BMJ Evidence-Based Medicine now ties alcohol to a higher dementia risk, with no safe consumption level.This study, drawing on data from over 500,000 participants in the UK Biobank and US Million Veteran Program (aged 56-72 at baseline, with nearly 15,000 dementia cases), used Mendelian randomization to examine gene variants tied to alcohol consumption. 

The results showed a steady rise in dementia risk with increased alcohol intake, with no evidence that moderate drinking offers protection. Observational data initially suggested a U-shaped curve, but this was likely skewed by reverse causation: people with early cognitive decline often reduce alcohol intake before diagnosis, creating a false impression of protection.

These findings align with the World Health Organization’s 2023 statement that no level of alcohol is safe and are supported by neuroscience research showing alcohol’s direct toxicity to brain neurons. It’s time to inform patients and the public that moderate alcohol consumption does not benefit the heart or brain. 

Clinicians should encourage reducing alcohol intake and discourage starting the habit for health reasons.